Balloon dilatation catheters are used to treat lesions in vessels. However, difficulties are encountered in navigating tortuous anatomy and safely crossing very tight lesions. Moreover, some lesions are difficult to crack using just a balloon, and require a focused force to enable cracking of the lesion at safe inflation pressures. In the past, others have proposed balloons with external wires for providing a focused force, such as in U.S. Pat. No. 8,070,729, the disclosure of which is incorporated herein by reference. The proposal for exposed wires (such as a core wire and a guide wire) adds to the manufacturing complexity. The specific locations required for the wires (which are asymmetrical in the proposed design of the '729 patent) and the full extension along the balloon also dictates the location or direction of the focused force provided, which contributes to a lack of control over these parameters.
Accordingly, a need is identified for a balloon and related dilatation catheter with enhanced flexibility in controlling the application of a focused force, such as for scoring or cracking lesions, and which can be manufactured in a simpler manner than past proposals.